The act of poking ones male genitalia through a bag of buttery popcorn you are sharing with a woman at the movies. When the women reaches for a handful of popcorn she acquires instead a handful of buttery penis. Thus the Buttery Serendipitous Handjob is created.

Trent- Grant got a Buttery Serendipitous Handjob at the movies from that hood-rat yesterday!